I have to pass the user environment language variable to APEX from EBS(as i have APEX integrated with EBS). Like as mentioned in docs

If the APEX application requires every session to
be initialized for the E-Business Suite user and
responsibility then this can be achieved by
entering a call to the
FND_GLOBAL.apps_initialize procedure into
Virtual Private Database (VPD) security attribute
for the APEX application like below
IF :FND_GLOBAL_USER_ID IS NOT NULL THEN
FND_GLOBAL.apps_initialize(
:FND_GLOBAL_USER_ID,
:FND_GLOBAL_RESP_ID,
:FND_GLOBAL_RESP_APPL_ID);
END IF;

I have a apex responsibility in EBS, in which soon after i clicked that responsibility it will redirect to the APEX home page(Without login page).

Inorder to take the USERENV('LANG') variable of EBS to APEX, as mentioned in docs they asked to do some apps initialization. I tried by passing like below

IF
*:FND_GLOBAL_USER_ID IS NOT NULL THEN* FND_GLOBAL.apps_initialize(0,50982,0);END IF;

where 0-> is the login ebs user id
50982-> is the responsibility id (where the apex is integrated in EBS)
0-> is the responsibility application id

I tried in the above manner for passing the ebs user language to the APEX for showing the data in the language they logged in via application. But it is not working.

I have to pass the user environment language variable to APEX from EBS(as i have APEX integrated with EBS). Like as mentioned in docs

If the APEX application requires every session to
be initialized for the E-Business Suite user and
responsibility then this can be achieved by
entering a call to the
FND_GLOBAL.apps_initialize procedure into
Virtual Private Database (VPD) security attribute
for the APEX application like below
IF :FND_GLOBAL_USER_ID IS NOT NULL THEN
FND_GLOBAL.apps_initialize(
:FND_GLOBAL_USER_ID,
:FND_GLOBAL_RESP_ID,
:FND_GLOBAL_RESP_APPL_ID);
END IF;

I have a apex responsibility in EBS, in which soon after i clicked that responsibility it will redirect to the APEX home page(Without login page).

Inorder to take the USERENV('LANG') variable of EBS to APEX, as mentioned in docs they asked to do some apps initialization. I tried by passing like below

But I don't see any code that derives USERENV('LANG') in your code

IF
*:FND_GLOBAL_USER_ID IS NOT NULL THEN* FND_GLOBAL.apps_initialize(0,50982,0);END IF;

This only initializes the apps session for the given values

where 0-> is the login ebs user id
50982-> is the responsibility id (where the apex is integrated in EBS)
0-> is the responsibility application id

I tried in the above manner for passing the ebs user language to the APEX for showing the data in the language they logged in via application. But it is not working.

Again I don't see any code that passes user language ..only thing I can see is of initializing apps/ebs session

Try following, whilst make sure FND_GLOBAL_USER_ID is not null when your apex is launched from EBS
create a application item called EBS_USER_LANG in your apex application

IF
:FND_GLOBAL_USER_ID IS NOT NULL THEN
FND_GLOBAL.apps_initialize(0,50982,0);
:EBS_USER_LANG :=USERENV('LANG');
END IF;

And then launch the apex app from EBS and check the value of EBS_USER_LANG in the APEX session state

I checked in the session state of that page item but it seems there is not any value set for that item. I logged into apex via(EBS by switching to Arabic 'AR', expecting my apex item :P16_EBS_LANG to capture the code 'AR' from EBS userenv('lang'))

I tried in that way too, that is under the security attributes in the pl/sql initialization block, i gave like below

IF
:FND_GLOBAL_USER_ID IS NOT NULL THEN
FND_GLOBAL.apps_initialize(0,50982,0);
:P16_EBS_LANG :=nvl(USERENV('LANG'),'NULL LANG');
END IF;

After that i navigated to the page 16 where my item :P16_EBS_LANG located, but still no any userenv lang is setted for that item, as i have logged in via EBS with Arabic language and also with the sysadmin user who has the userid-->0

i checked in session state too, but then too i couldnt see any value for that item.

I tried in that way too, that is under the security attributes in the pl/sql initialization block, i gave like below

Try this code into a on-load before header application process

IF
:FND_GLOBAL_USER_ID IS NOT NULL THEN
FND_GLOBAL.apps_initialize(0,50982,0);
:P16_EBS_LANG :=nvl(USERENV('LANG'),'NULL LANG');
END IF;

After that i navigated to the page 16 where my item :P16_EBS_LANG located, but still no any userenv lang is setted for that item, as i have logged in via EBS with Arabic language and also with the sysadmin user who has the userid-->0

Don't NAVIGATE AWAY TO ANY PAGE, JUST CHECK the session state as soon as you launch the apex from ebs.

i checked in session state too, but then too i couldnt see any value for that item.